The purpose of this study is to see how antibodies (proteins that fight infection) are made after you receive the new H5N1 flu vaccine. The new H5N1 vaccine will be given to 50 healthy adult lab workers, aged 18 years and older. Subjects will receive two 90mcg injections (shots in the arm) of the vaccine about 1 month apart. Subjects will maintain a memory aid to record oral temperature and any response to the vaccine for 7 days after each immunization. Subjects will be contacted by telephone 1 to 3 days after vaccination. They will return to the clinic on Day 7. Blood will be drawn before each vaccination and on Days 56 and 180. Subjects may be involved in the study for about 6 months. It is anticipated that the vaccine will provide safe protection against influenza H5N1.